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Study links nutrition to brain health and cognitive aging

A new study of older adults finds an association between higher blood levels of phosphatidylcholine, a source of the dietary nutrient choline, and greater cognitive flexibility, the ability to regulate attention to manage competing tasks. The study also identified a brain structure within the prefrontal cortex, a region at the front of the brain, that appears to play a role in this association.

Phosphatidylcholine (pronunciation) in the blood can originate from the diet, said University of Illinois graduate student Marta Zamroziewicz, who led the study with Aron Barbey, a professor of psychology and an affiliate of both the IGB and the Beckman Institute. Egg yolks, red meat and soybeans are rich sources of phosphatidylcholine, which also can be synthesized by the body, she said. Phosphatidylcholine is a key component of cell membranes.

“Accumulating evidence suggests that declining phosphatidylcholine levels are a robust marker of age-related neurodegeneration and cognitive deterioration,” Zamroziewicz said. “No studies have determined how phosphatidylcholine may prevent such decline, however,” she said.

The new analysis, reported in the journal Frontiers in Aging Neuroscience, measured blood levels of phosphatidylcholine and assessed brain structure in 72 healthy adults between the ages of 65 and 75. The researchers used magnetic resonance imaging to gauge the thickness of gray matter in the prefrontal cortex.

The researchers conducted statistical analyses to tease out the relationships between phosphatidylcholine levels, brain structure and performance on specific cognitive tests. They controlled for age, sex, education, income, depression status and body-mass index, and focused on specific regions within the prefrontal cortex.

“We hypothesized that higher blood plasma levels of phosphatidylcholine would be associated with better performance on tests of cognitive flexibility,” Zamroziewicz said. “And we found that higher blood levels of phosphatidylcholine are linked to better cognitive flexibility.”

The analyses also linked gray-matter thickness of the left inferior prefrontal cortex to better cognitive flexibility, and revealed that the beefiness of gray matter in this brain region played a role in the relationship between phosphatidylcholine levels and performance on tests of cognitive flexibility.

“Our findings add to a growing body of research suggesting that particular nutrients may slow or prevent age-related declines in cognition by influencing specific structures within the brain,” Barbey said. “We don’t yet know all the mechanisms involved. It may be that phosphatidylcholine protects the brain from the effects of aging by supporting the structure of brain membranes, reducing inflammation or contributing to the production of neurotransmitters that support cognition.”